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 Post subject: MSR projects in the UK
PostPosted: Sep 27, 2014 10:46 am 
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http://nextbigfuture.com/2014/09/molten ... .html#more
Taking one of the suggested MSR projects could be beneficial to UK in two ways:-
1. A rational use of RG plutonium stocks.
2. After initial development, lower power costs than the EPR, the costliest PWR in the world.


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PostPosted: Nov 16, 2014 11:28 am 
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It is not well-known, but the UK had a multi-million MSFR R&D programme in the 1960s and early 1970s, focusing on chloride salts:

http://www.the-weinberg-foundation.org/ ... programme/

The R&D documents are not in digital form yet, but are stored at the UK National Archives. The Alvin Weinberg Foundation will be working on digitising the documents.


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PostPosted: Nov 16, 2014 1:17 pm 
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Here is one of them, which I digitized many years ago:

http://energyfromthorium.com/pdf/AEEW-R956.pdf


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PostPosted: Nov 16, 2014 4:03 pm 
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I read the study AEEW-R956 a few years ago. Many of the comments seems to be based on R&D. The size of 2500 MWe was extremly large end of the 60ies. Most probably they wanted to compensate the complexity disadvantage of a MSR by increasing the size.

As they did some engineering work and practical testing was not that difficult as today...Are there any additional studies available from this group about....

The mixing and seperating of chloride salts and lead?
The corrosion of Mo-TZM in chloride salts?
The physical properties of molten chlorides?
The plating out of noble fission products?


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PostPosted: Nov 17, 2014 6:19 am 
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HolgerNarrog wrote:
I read the study AEEW-R956 a few years ago. Many of the comments seems to be based on R&D. The size of 2500 MWe was extremly large end of the 60ies. Most probably they wanted to compensate the complexity disadvantage of a MSR by increasing the size.

As they did some engineering work and practical testing was not that difficult as today...Are there any additional studies available from this group about....

The mixing and seperating of chloride salts and lead?
The corrosion of Mo-TZM in chloride salts?
The physical properties of molten chlorides?
The plating out of noble fission products?


This remains to be seen, the British researchers carried out several tests, but the research documents and results are still in physical form and it is not clear what they researched, as much of it was classified information. The Alvin Weinberg Foundation will make the documents public once they have been digitised.


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PostPosted: Dec 04, 2014 4:20 pm 
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Thank-you all. I was interested to find the British developers, and also the historic research. I've thought for a while that MCFBRs were a more logical development than sodium-cooled FBRs.

Though not as safe as LFTRs, with fast neutrons it seems likely that MCFBRs have higher power density, more choices for fuel, and less need for a pesky fragile moderator.


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PostPosted: Dec 14, 2014 4:34 pm 
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I prefer the MCFR design vs. the MSFR design very much. The vintage graphite moderated MSR seem to me out anyway.

There are plenty of pro`s and con`s for both options...

The MCFR has a very hard neutron spectra and thus a high breeding ratio or you can run it with a high share of fission products
The chlorides have lower boiling points which makes the reprocessing much easier but requires some pressure in the primary circuit.
The fluorides have a higher heat capacity which is an advantage in engineering HX and pumps.
The corrosion challenge is worse with the chlorides. It most probably requires molybdenum alloys as structure material while the fluoride reactor might use nickel based materials for most of the components.
............

Best regards

Holger


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PostPosted: Dec 14, 2014 11:02 pm 
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HolgerNarrog wrote:
There are plenty of pro`s and con`s for both options...
To me the worst "con" for MCFRs is that you need isotopically pure Cl37.
That's almost as bad as pure Li7 in FLiBe.


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PostPosted: Dec 14, 2014 11:50 pm 
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jaro wrote:
HolgerNarrog wrote:
There are plenty of pro`s and con`s for both options...
To me the worst "con" for MCFRs is that you need isotopically pure Cl37.
That's almost as bad as pure Li7 in FLiBe.
No. HCl is easy to gasify. Li-anything is not. Centrifuges will work very easily with HCl.

_________________
DRJ : Engineer - NAVSEA : (Retired)


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PostPosted: Dec 15, 2014 2:01 am 
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KitemanSA wrote:
No. HCl is easy to gasify. Li-anything is not. Centrifuges will work very easily with HCl.
Sure.
You could even use tertrachloromethane, CCl4, but it still means you have to go to some outfit with centrifuges and beg them to do a small batch for you -- after cleaning out their entire cascade of whatever it is they normally process. Sounds very expensive to me.


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PostPosted: Dec 15, 2014 7:40 am 
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Well someone makes isotopically enriched chlorine these days (Its used for various analytical stuff).


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PostPosted: Dec 15, 2014 5:28 pm 
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We had the discussion about the 35Cl a couple of times in this forum....

The main real issue is the 35 Cl (n,alpha) reaction that creates sulphur. Sulphur is corrosive. According to Merle-Lucotte INP it calculates to 10 mols/yr in a large reactor. This quantity should not be of major concern.

Acc. to E. Merle-Lucotte another about 10 moles/yr. of 36Cl/yr. is created in a MCFR as well. 36 Cl is slightly radioactive with a long half time. In the MCFR it is foreseen to reuse the salts in the reactor. As the salts needs to be treated protected from the atmosphere to avoid impurities it should not increase the costs significantly. As the salt residues forseen for storage contain residues of Pu, U, and fp (there is no 100% seperation!) these residues are anyway radioactive and have to be treated as radioactive waste. It is an artifical challenge as many in nuclear.


Last edited by HolgerNarrog on Dec 15, 2014 11:31 pm, edited 1 time in total.

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PostPosted: Dec 15, 2014 8:10 pm 
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HolgerNarrog wrote:
The main real issue is the 35 Cl (n,alpha) reaction that creates sulphur.
I am not familiar with an Cl35(n,alpha) reaction.
Anyway, that would produce phosphorus, not sulphur.

The reaction of concern is Cl35(n,p)S35.
It eats lots of fast neutrons (about 100x that of the n,g reaction), besides producing sulphur.


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PostPosted: Dec 15, 2014 11:28 pm 
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Dear Jaro,

35P decays to 35S, half time 47s

The neutron spectrum of an MCFR is very hard and thus the cross sections small.

Holger


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PostPosted: Dec 16, 2014 3:56 am 
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HolgerNarrog wrote:
The neutron spectrum of an MCFR is very hard and thus the cross sections small.
Yes they are normally small.

Except for the Cl35(n,p)S35 reaction....


Attachments:
Cl35,37_Na23_(n,P)_(n,g)_fast.gif
Cl35,37_Na23_(n,P)_(n,g)_fast.gif [ 61.69 KiB | Viewed 6844 times ]
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